<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
//关于函数的作用域的JS代码
</body>
<script>
    function fun1()
    {
        var i=0
        //alert(i)
        function fun4()
        {
            var j=1
            fun2()
            // alert(j)
        }
        fun4()
    }
    fun1()
    function fun2()
    {
        var h=2
        alert(h)
        function fun3()
        {
            var m=3
           // alert(m)
        }
        fun3()
    }
    fun2()

</script>
</html>